Properties of D-branes in matrix model of IIB superstring

Physics Letters B, 2001

Type IIB superstring models with the standard model gauge group on D3-branes and with massless matter associated with open strings joining D3-branes to D3-branes or D3-branes to D7 3-branes are studied. Models with gauge coupling constant unification at an intermediate scale between about 10 10 and 10 12 GeV and consistency with the observed value of sin 2 θ W (M Z) are obtained. Extra vector-like states and extra pairs of Higgs doublets play a crucial role.

Journal of High Energy Physics, 2002

We present a maximally supersymmetric IIB string background. The geometry is that of a conformally flat lorentzian symmetric space G/K with solvable G, with a homogeneous fiveform flux. We give the explicit supergravity solution, compute the isometries, the 32 Killing spinors, and the symmetry superalgebra, and then discuss T-duality and the relation to M-theory.

Physical Review D, 1999

We present a geometric formulation of type-IIA and-IIB superstring theories in which the Wess-Zumino term is second order in the supersymmetric currents. The currents are constructed using supergroup manifolds corresponding to superalgebras: the IIA superalgebra derived from M-algebra and the IIB superalgebra obtained by a T-duality transformation of the IIA superalgebra. We find that a slight modification of the IIB superalgebra is needed to describe D-string theories, in which the U(1) gauge field on the worldsheet is explicitly constructed in terms of D-string charges. A unification of the superalgebras in a (10 + 1)-dimensional N = 2 superalgebra is discussed too.

Physics Letters B, 1998

It is well-known that the low energy string theory admits a non-singular solitonic super five-brane solution which is the magnetic dual to the fundamental string solution. By using the symmetry of the type IIB string theory, we construct an SL(2, Z) multiplet of magnetically charged super five-branes starting from this solitonic solution. These solutions are characterized by two integral three-form charges (q 1 , q 2) and are stable when the integers are coprime. We obtain an expression for the tension of these (q 1 , q 2) five-branes as envisaged by Witten. The SL(2, Z) multiplets of black strings and black fivebranes and the existence of similar magnetic dual solutions of strings in type II string theory in D < 10 have also been discussed.

Journal of High Energy Physics, 2000

We provide a classification of the IIB Dp-and NSp-branes in which the brane action exists due to a non-trivial class of the Chevalley-Eilenberg cohomology of free differential algebras. We then present a new geometric formulation of the IIB Dp-and NSp-branes (p ≤ 5) in which the manifestly superinvariant Wess-Zumino terms are constructed in terms of the supersymmetric currents. The supercurrents are obtained by using supergroup manifolds corresponding to the IIB-brane superalgebra, which is characterized by the generators of D3-, D5-, NS5-and KK5-branes in addition to the previously introduced generators of supertranslations, F-and D-strings. The charges of D1-, F1-and D3-branes are related to those of the M-algebra, but some charges of D5-and NS5-branes are not. The S-duality of the type-IIB theory is realized as transformations of the supercurrents generalizing the SO(2) R-symmetry of the superalgebra. We thus find that the superalgebra is lifted into twelve-dimensions with signature (11,1).

Nuclear Physics B, 2001

Open superstring theory is formulated in terms of a nondegenerate supertranslation algebra. A supercharge for a tachyonic superstring can be also defined classically by taking into account the leakage of the supercurrent which is compensated by fermionic and bosonic auxiliary fields. The anticommutator of two supercharges of the tachyonic superstring does not contain the zero eigenvalue and so this string is not a BPS state. Brane-antibrane annihilation scenarios are described by these superalgebras defined on the sum of world-volumes of a D-brane, an anti-D-brane and a tachyonic superstring.

Nuclear Physics B, 1997

Via compactification on a circle, the matrix model of M-theory proposed by Banks et al suggests a concrete identification between the large N limit of two-dimensional N = 8 supersymmetric Yang-Mills theory and type IIA string theory. In this paper we collect evidence that supports this identification. We explicitly identify the perturbative string states and their interactions, and describe the appearance of D-particle and D-membrane states. * Here we work in string units α = 1. A derivation of (1) from matrix theory and a discussion of our normalizations is given in the appendix.

Modern Physics Letters A, 1997

We calculate an effective action and measure induced by the integration over the auxiliary field in the matrix model recently proposed to describe IIB superstrings. It is shown that the measure of integration over the auxiliary matrix is uniquely determined by locality and reparametrization invariance of the resulting effective action. The large-N limit of the induced measure for string coordinates is discussed in detail. It is found to be ultralocal and, thus, possibly is irrelevant in the continuum limit. The model of the GKM type is considered in relation to the effective action problem. *

Nuclear Physics B, 2002

We study a class of type I string models with supersymmetry broken on the world-volume of some D-branes and vanishing tree-level potential. Despite the non-supersymmetric spectrum, supersymmetry is non-linearly realized on these D-branes, while it is spontaneously broken in the bulk by Scherk-Schwarz boundary conditions. These models can easily accommodate 3-branes with interesting gauge groups and chiral fermions. We also study the effective field theory and in particular we compute the four-fermion couplings of the localized Goldstino with the matter fermions on the brane. * On leave of absence from CPHT, Ecole Polytechnique, UMR du CNRS 7644. 1 The parameter C f is related to the parametrisation of other authors by C f = − α 4 [17] = C f f 2 [18].

We construct four dimensional intersecting D6-brane models that have locally the spectrum of the N=1 Supersymmetric Standard Model. All open visible string sectors share the same N=1 supersymmetry. As expected in these supersymmetric classes of models, where the D6-branes wrap a toroidal orientifold of type IIA, the hierarchy may be stabilized if the string scale is low, e.g. below 30 TeV. We analyze the breaking of supersymmetry in the vicinity of the supersymmetric point by turning on complex structure deformations as Fayet-Iliopoulos terms. Positive masses for all squarks and sleptons, to avoid charge/colour breaking minima, may be reached when also two loop contributions may be included. In the ultimate version of the present models N=1 supersymmetry may be broken by gauge mediation. The constructions with four, five and six stacks of D6-branes at M s are build directly. Next by the use of brane recombination we are able to show that there is a continuous, RR homology flow, between six, five and four stack models. Moreover, we examine the gauge coupling constants of the Standard Model SU(3) C , SU(2) L , U(1) Y at the string scale in the presence of a non-zero antisymmetric NS B-field.